1
An ideal monatomic gas of n moles is taken through a cycle WXYZW consisting of consecutive adiabatic and isobaric quasi-static processes, as shown in the schematic V-T diagram. The volume of the gas at W, X and Y points are, 64 cm3, 125 cm3 and 250 cm3, respectively. If the absolute temperature of the gas TW at the point W is such that nRTW=1 J (R is the universal gas constant), then the amount of heat absorbed (in J) by the gas along the path XY is [figure]
Answer
1.6
Solution
On a V-T diagram an isobar is a straight line through the origin: XY and ZW are isobaric; WX and YZ are adiabatic (TV -1= const, = 53).
W X: TX=TW ( VWVX )2/3=TW ( 64125 )2/3= 1625TW
X Y (isobaric): TY=TX VYVX=2TX, so T=TX
QXY=nCp T= 52nRTX= 52 1625 1=1.6 J
Answer: 1.6
JEE Advanced 2025 Paper 2